The present invention relates to so-called U-frame trucks for handling and transportation of containers or receptacles.
The last 10 to 15 years such U-frame trucks have often been used at mining and steel-making plants. Our truck "Kiruna Combi K-250" is such a truck.
Such a truck comprises a prime mover including a motor and a transmission, and a trailer having an outer and inner U-shaped frame. The outer frame is connected to the prime mover and comprises the wheel assemblies and a couple of hydraulic cylinders, usually three or four. Two cylinders are placed at the back adjacent the open end of the frame, and one or two cylinders are placed at the front. The hydraulic cylinders carry or support the inner frame, which in turn supports the container. The hydraulic cylinders make the container tiltable.
At operation, the truck is simply driven such that it is moved backwards to a container standing on the ground. The open end of the U-frame is turned backwards and is moved backwards such that the U-frame will enclose the container at three sides. At this moment the inner frame is lowered to its lowest position. Thereupon, the hydraulic cylinders are activated and lift the inner frame such that it co-operates with the container at its border and lifts the container. The hydraulic cylinders are stopped in a transport position, where the container is lifted from the ground about half a meter.
It is understood that the container can be tilted by rising only the front hydraulic cylinders. The container is prevented from sliding down from the inner U-frame by suitable stop means.